X Factor judge Sharon Osbourne has quit the show after four series. Unlike previous claims in a similar vein, it appears that this announcement is not a publicity stunt as it has been confirmed by ITV, although conspiracy theorists will notice the timing is very similar to last year's hoo-hah surrounding Leprechaun Louis, coming as it does at the start of the audition process for the 2008 series, due to be aired in September.

No reason for Mrs O's departure were given, but it's no secret there were behind-the-scenes clashes between the judges last year, especially involving Sharon and "new girl" Dannii Minogue. It can't have helped that Sharon's acts were the first to leave the contest and she was the first judge to be left without an act to mentor, although she put a positive spin on this at the time saying she was the only member of the panel who could be completely impartial.

The London auditions are due to start on June 12, and until today the expectation was that Sharon would be joining the rest of the panel for business as usual.

A statement from ITV makes the usual noises thanking her for her contribution and wishing her well, but there is no mention of negotiation in the announcement, which appears to be a fait accompli. Cynics amongst us remain to be convinced that she won't have a last minute change of heart and appear on the show in the end. [via MG]